Fluid that is pumped from the ground is generally mixed with solid impurities such as sand, pebbles, limestone, and other sediment and debris. Certain kinds of pumped fluids, such as heavy crude, tend to contain a relatively large amount of solids. Because of these impurities, a number of problems are regularly encountered during fluid pumping operations.
Solid impurities can be harmful to a pumping apparatus and its components for a number of reasons. Conventional gear pumps, for example, are particularly susceptible to wear and damage from solid impurities that become entrained in the pump components during pumping operations. These solid impurities can cause damage, reduce effectiveness, and sometimes require a halt to pumping operations and replacement of the damaged components. In conventional gear pumps fluid is pumped using an upward and downward motion only, which requires more strength and force than a side-to-side motion. The exertion that conventional gear pumps undergo causes wear and tear on the gear pumps, eventually resulting in pump failure over time and a need for replacement pump components or a replacement pump altogether. This can be both time consuming and expensive.
Conventional rotary and reciprocating pumps that use gear, cams, and fins to move fluid are not efficient and become damaged when pumping high solids fluid. Most pumps of these designs use a rotary motion to move fluid. Rotation of fluid can create a centrifugal motion which causes solids to move outward to the outer regions of the pump wall. With this type of design, solids can be swept to the outer wall where they accumulate as high density slurry. The slurry can then be swept in a rotation motion where there is clearance between the pump components. This clearance can allow the concentration of solids to be forced into areas of tolerance causing abrasive damage to the rotor and stator. This damage can cause more tolerance and thus allow less fluid to be pumped at a given rpm. The solids can also cause the pump to seize and result in the pump being pulled out of service. This cost can be significant when the pump is in critical areas of fluids production.
The present application addresses these problems encountered in prior art pumping systems and provides other, related advantages.